Exposure apparatuses are commonly used to transfer images from a reticle onto a semiconductor wafer during semiconductor processing. A typical exposure apparatus includes an illumination source, a reticle stage assembly that retains a reticle, a lens assembly, a wafer stage assembly that retains a semiconductor wafer, a metrology system that monitors the position of the stage assemblies, and a control system that controls the stage assemblies based on the position information from the metrology system. Typically, the wafer stage assembly includes a wafer stage base, a wafer stage that retains the wafer, and a wafer stage mover assembly that precisely positions the wafer stage and the wafer. Somewhat similarly, the reticle stage assembly includes a reticle stage base, a reticle stage that retains the reticle, and a reticle stage mover assembly that precisely positions the reticle stage and the reticle.
Unfortunately, the stage mover assemblies generate heat that can adversely influence the other components of the exposure apparatus. For example, the heat can distort certain components and/or adversely influence the measurements taken by the metrology system. Conventionally, the stage mover assemblies are cooled by forcing a coolant around the movers of the stage mover assembly. However, it is often very difficult to adequately or efficiently cool the stage mover assemblies. Accordingly, there is a never ending goal to improve the efficiency of the stage mover assemblies to reduce the amount of heat generated by the stage mover assemblies.